Not sure if this is the right place to put this, so sorry if its not! Anyways Ive got the mods in my sig and I've played with the truck a little bit, nothing too hard but now whenever im taking off and the truck goes to shift it feels like Im letting off the gas before it shifts. Its most noticeable in the 1-2, 2-3 and 3-4 shifts and then it mellows out. Whats causing this? Does my programmer need to be updated to get rid of this? Is my tranny takin a dump?

Is it when you are under hard accelleration? If so, then
it's the defuel in the engine programming to keep from hurting your tranny, and it is normal.

JT

i can get it to do it when just driving normal too sometimes but its not as obvious.

How many miles have you got on that thing? Mine started to do this when the fuel filter took a crap. Change it out and see what happens. My first one went out around 8 or 9 thousand miles. I've seen them get clogged before that though. Mine felt like it hit a wall at about 2900RPMS, then after a few days it started to do it sooner... eventually clogging completely and throwing my truck into limp.

ive already replaced the filter once....at like 2k miles and now im at 2900 and the DIC says i still have 95% fuel filter life.

Mine does it too. I think some of it is in the programming, but its also kind of just the nature of the allison transmission. With tow/haul on mine seems to shift a lot better.

What you guys describe is a function of the shift process and originates in the transmission. Defuel can be reduced or eliminated in the transmission tune file. It can be decreased some in the engine tune (quad is an engine tuner).

Hope this helps,

Nick

What version of the Quad tunes are you running? If you have an older version, say 2.26, there was a LOT of defuel on shifts. The newest version should have much less noticeable defuels.

Plug in your Quad to the truck and look at the first couple of boot up screens. That will tell you the version you are on. Current is 2.4 and if you are much below that you can definitely improve by updating the tune files in your Quad..

BTW, very important... If you do update the Quad, make sure to return truck to stock first, then update the Quad, then install your desired tune...